Controlling mechanism for electric motors.



No. 872,289. PATENTED NOV. 26, 1907.

E. D. LEWIS.

CONTROLLING MECHANISM FOR ELECTRIC MOTORS.

APPLIOATION FILED JUNE 18. 1907.

2 SHEETB-SHEET 1.

WWI/110110711 'II/IIIII/ I I Y WITNESSES: \NVENTOR ATTORNEY No 872,289.PATENTED NOV. 26, 1907.

' E. D. LEWIS.

CONTROLLING MEGHANISMFOR ELECTRIC MOTORS.

APPLICATION FILED JUNIZ18, 1907.

'2 sums-sum z.

WITNESSES INVENTOR 14, 6, MM? ggwma wag WW ATTORN EY UNITED STATESPATENT OFFICE.

EDWARD D. LEWIS, OF ELMIRA, NEW YORK, ASSIGNOR TO LEWIS MOTOR & CRANECOMPANY,

A CORPORATION OF MAINE.

Specification of Letters Patent.

Patented Nov. 26, 1907.

Application filed June 18. 1997- Sm-ial No. 379,556:

To all whom it may concern:

Be it known that 1, EDWARD D. Lnwis, a citizen of the United States,residing at Elmira, in the county of ()hemung and State of New York,have invented certain new and useful improvements in ControllingMechanism foriiilectric Motors, of which the following is aspecification.

This invention relates to improvements in the means for stopping,starting and reversing electric motors; and the object of myimprovements is to provide a switch, in combination with asystem ofwiring at and be tween the switch and motor, whereby, when starting themotor in either direction, the field will be saturated in advance of thearmature, the armature being entirely out out during this initialsaturation of the field. A quick and strong starting-torque will thushave been produced in the iield magnets just before the armature is cutin.

A further object is to accomplish the stopping of the motor by cuttingout the armature in advance of the field, and utilizing the full currentto energize the field magnets after the armature cut out, thereby producing a strong and effective retarding force in the motor itself toquickly arrest the motion of the armature.

I attain my objects by a switch constructed and connected with a motorin the manner illustrated in the accompanying drawings, in which Figure1 represents a front elevation of the switch together with adiagrammatic illustration of a series wound motor, and the connectionsbetween the motor and the switch; Fig. .2, a sectional view of theswitch looking to the left on the line c.a in Fig. 1; and Fig.

3, an illustration of the switch as applied. to a shuntwound motor.

Like numerals and letters of reference indicate like parts in theseveral views.

In applying my invention to a series wound motor, I )rovide asupplementary resistance which shall be the equivalent of the armature,and in order to utilize this resistance for the purpose of impartingadditional magnetic force in the field of the motor, 1 arrange theresistance in the form. of coils of wire wound around and insulated fromthe field coils, said resistance coils being connected with the fieldcoils in series and having the current passed through in the samedirection as it passes through the field coils.

This arrangement of the field and resistance coils will be understoodfrom an inspection of Fig. 1, wherein 11 indicates the resistance coilsand 16 the field coils.

The switch'and connections for operating this motor are arrangedasfollows: The switch consists of a base, or backplate 1, of insulatingmaterial, having a series of contacts arranged thereon in a circlearound a central pivot pin 5. These contacts are in the form of metalbuttons projecting slightly beyond the face of the back-plate, and areindicated by the designating letters to which reference will be madehereafter. These contacts are provided at the back of the plate 1 withbinding posts to receive the connecting wires; and the pivot pin 5 isconnected' by means of a binding post with one branch of the currentsupply loop; this main supply wire being indicated by the numeral 9.

Mounted upon the pivot pin 5 is a disk 2 of insulating material, havingthe extensions 3 and 3h projecting from opposite sides thereof andconstituting a rock arm by which the switch is operated. The disk 2 isof insulating material, and, at diametrically opposit-e sides, isprovided with the contact plates 4 and 6, plate 4 being provided with ahub which engages the pm 5, thereby placing said plate in connectionwith the supply wire 9. This plate 4 1s a narrow strip of metal whichprojects beyond the disk '2, in position to engage the contactsseparately as the rock arm is turned in one direction or the other. Theplate 6 is insulated by the disk 2 from the plate 4, and ismadesufficiently broad to span the space between a air of contactspositioned on either side tiereof.

, To hold the rock arm in mid osition, and to return it automatically tosue i osition when the arms 8 or 3L are released, may (provide a coiledspring 7 attached to a fixe in 8. This feature, however, is not essentiaand may be omitted if desired.

At each side of the contact-plate 4 are the contacts marked R and KL,connected together by a wire, said wire running thence to one end of theresistance coils. This wire 10 is shown connected with the outer coil ofthe upper resistance 11, the inner coil of said resistance beingconnected by wire 12 to the inner coil of the lower resistance 11, andthe outer coil of said lower resistance being connected in turn by thewire 13 with the wire 15, which runs to the outer coil of the lower thusproviding a continuous circui tact plate 6, marked respectivel AAL and-AA, and are'thence connected wires 19 with the armature brushes. Adacent the contact plate 6, and at each side thereof are the contacts Fand FL, connected together, and by the wire 15 connected with the field.

The 0 ration of the switch and the motor governe thereby will be asfollows :When

the switchis in the position shown in Fig. 1 no current will be passingthrough the motor. To start-the motor in one direction, the arm 3will'be pulled down until contact plate 4 engages contact R, the currentwill then pass from wire 9, through plate 4 and contact R, through wire10 in the direction indicated by the arrow marks into and through theresistance co ils, thence by way of wires 13 and 15 into and through thefield coils, and out by way of the .wire 18 to themain supply cir--cuit, thereby carrying the entire current around the field magnets andtherein a strong starting torque. he arm 3 is now pulled still fartherdown, therebcausing the plate 4 to pass from contact into engagementwith contact A, cutting out the resistance and causing the current topass from wire 9 through contact A and, by way of the wires 19 and thebrushes, through the armature, the armature circuit being completedthrough contact AA, which is now connected by plate 6 with contact F,-said plate 6 bridging the distance between said contacts AA and-F whenplate 4 is in engagement with contact A. The current therefore nowpasses from the armature directly into the field coils by'way of contactF and wire 15, and thence out through return wire 18.

The motor willytherefore, be uickly started, and will continue to run atfu 1 speed until it is desired to stop it. If the motor is to be run atdifferent speeds, any approved speed controller may be connected in withwire 9.

In stopping the motor, the arm 3 will be moved back to its originalposition, either ,by the operator, 'or automatically, by the spring 7,when the arm is released. In passing back to their open positions, thecontact plates .4 and 6 first cut out the armature, the

resistance'being cut in ,at the same time, thereby reventingthe fullcurrent from passing t ough the field coils and burning them out; also,during-this period of en agement of plate 4 with contact R, the fulcurrent will bepassing through'the resistance producing other throng AA,which'is connected by plate 6 with con- ,19 and back to contact AAL inreversed direction, and thence-through. plate 6 and contact FL to thefield; without, however, changing the direction of the current throughthe field; thus reversing the armature poles,

and causing the armature to run in the reverse direction.

Torevent drawing an are from contacts" R or L when plate 4 passeslout ofengagement th'erewith, .Iprovide snap springs 21,

which are engaged by the pin 20' on plate 4. As said plate passes 'oflfrom the contacts, said springs, when released from the pin 20, fly backto normal position, thereby reaking the are.

In shunt, wound motors the field coils will take the full current whenthe armature is cut out, and there is, therefore, no need of theresistance. The switch will be wired to such a motor in the mannerillustrated in Fig. 3. Here I have marked the first contact of/eachupper-pair F and FL, as they are connected directly with the field,instead of being-connected to the field through the resistance, as inthe series wound moton Also the plate 4 is made broader, so as to bridgethe distance between the field and armature contacts, when the motor isrunning. In start- 'ing this motor, when arm 3 is pulled downward, plate,4 will first engage contact F thereby causing the current to flow byway .of wire 15 throu h the field coils, and thence by wire-'18, whic isnow connected with the contacts FFL and FF back to the supply circuit,-thus saturating the field befor the armature is cut in. Asthe arm 3 ispulled still further down, plate 4 engages contact A and, being still inengagement with contact F, the current from wire 9 s lits, art of itcontinuing to pass through t e fiel and the part passing, by way. ofcontact A,

the armature and thence tocontact tact FF; the current shunted throughthe armature being thus brought back into the wire 18. At 22, I placestops by which the plate 4 is prevented'from being thrown beyond thepoint where it will short circuit the sistance the equivalent tion ofthe current through the field remain- 1 ing the same.

This controlling device is especially adaptl 1. The combination, with amotor, of a reof the armature, a switch, and conductors connecting thefield, the armature and said resistance with separate contacts ontheswitch, whereby in starting the motor the current will be applied to thefield and the resistance simultaneously and afterwards to the armature,the resistance being cut out when the armature is cut in, and whereby instopping the motor the resistance will be cut in when the armature iscut out. l 2. The combination, with a motor, of resistance coils woundaround the field coils and connected in series therewith, a switch andconductors connecting the field,' the armature and the resistance withseparate conl tacts on the switch, whereby in starting the motor thecurrent will be applied to the rel sistance and thence to the field andafterl wards to the armature and thence to the field, the resistancebeing cut out when the l armature is cut 1n, and whereby in stopping themotor the armature will be cut out an to secure by Letters Patent is i lof contacts adapted to be engaged by the l the resistance cut in andsubsequently the resistance and field cut out.

3. The combination, with a motor, of a switch comprisin a rock armhaving two oppositely dispose contact plates I mounted thereon andinsulated from one another, one of said plates beingconnected with thecurrent supply, a pair of contacts adapted to be engaged'by said currentsupply plate, and a pair of contacts adapted to be enga ed by the otherplate, the first contact of eac pairbe ing in circuit with the field andthe second contact of each pair being in circuit with the armature. p

4. The combination, with a motor, of a switch comprisin a rock armhaving two oppositely dispose contact plates mounted thereon andinsulated from one another, one of said plates being connected with thecurrent supply, a pair of contacts adapted to be engaged by said currentsupply plate, a pair other plate, the rst contact of each pair being incircuit with the field and the second contact of each pair being incircuit with the armature, and two other pairs of contacts laced onopposite sides of It e contact plates iiom' the first pairs andconnectedin like manner with the field and armature circuits whereby the motormay be reversed when the arm is turned in the o osite direction.

In testimony whereof ave affixed my signature, in presenceof twowitnesses.

EDWARD D. LEWIS. WVitnesses:

' M. E. VERBEOK,

L. V. STOELTZLEN.

